Dancing Raisins: Thanksgiving DIY Activity

This experiment is all about density and buoyancy. Soda water contains carbon dioxide (CO2) gas that has been dissolved under pressure. When you pour it into a glass, the gas starts to escape as tiny bubbles. Those bubbles attach to the raisins, and a raisin with bubbles stuck to it is less dense than the water around it. Buoyancy is the upward force from a fluid that makes things rise or float, so the raisin floats to the top.

Once a raisin reaches the surface, the bubbles pop. Without the CO2 bubbles holding it up, the raisin becomes more dense than the water again and sinks to the bottom. Then new bubbles attach, and the whole process repeats. The raisins keep switching between floating and sinking, and that's what makes them dance.

In plain tap water, no gas is coming out of solution, so no CO2 bubbles form. Any bubbles that cling to the raisins don't lift them, so gravity keeps them at the bottom. Smaller raisins tend to dance better.

If something as simple as gas bubbles can make raisins dance, what else around you is moving because of invisible forces? Science is always happening, even in a glass of soda water.

Try it yourself: Run the experiment again, but change only one variable at a time, like the size of the raisin or the food you drop in, such as cranberries, carrots, or apple slices. Predict which food will dance the best before you test it.